Carbon cycling

Autotrophs take carbon and make

organic matter (glucose) and oxygen

Organisms carry out respiration to release energy in the form of

ATP, carbon dioxie is a waste product

three main categories of organisms that carry out respiration

autotrophs, heterotrophs, saprotrophs and decomposers

CO2 (water)

some CO2 will dissolve and some will combine with water to become carbonic acid

Some animals secrete calcium carbonate to protect themselves

shells of molluscs, hard corals exoskeletons

Animals die and body decompose but calcium carbonate remain to

form deposits on the ocean floor

Deposits left behind are

buried and compressed to form limestone rock

Imprints of hard body parts remain in rocks

as fossils

Peat forms when

organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils

Peat burns

easily and can be used as a fuel

Peat is an effective

carbon sink, 500Gt of carbon in peat

Process of Peat formation

-In soil, organic matter, are digested by saprotrophic bacteria and fungi

-Saprotrophs assimilate some carbon for growth and release as carbon dioxide during aerobic respiration (Requires oxygen)

-Water logged soils are aneaerobic so saprotrops and decomposers-methanogens

-Organic matter is only partially decomposed

-Build up of organic matter

-Organic Matter is compressed to form peat

How is coal formed

when deposits of peat are buried under other sediments. Compressed, and heated (peat)

Oil and gas formation

occurred in ancient oceans

If heated, dried biomass or fossilized fuels will

burn in the presence of oxygen

methanogens are

archaean microorganism that produce methane as a metabolic byproduct in anoxic conditions (oxygen limited)

Methane is typically produced from

carbon dioxide

Methanogens are found in a variety of anoxic environment

-wetland

-digestive tracts of animals

-marine and freshwater sediments

-Landfill sites

Trend in CO2 levels

constantly increasing

Why does CO2 levels change between seasons?

During spring and summer, there are more leaves to photosynthesize; in winter and fall, there are fewer leaves, and they cannot photosynthesize as much. More photosynthetic activities decreases CO2 levels because plants turn carbon dioxide into glucose and oxygen.